Phase stable rare earth garnets

Abstract

A transparent ceramic according to one embodiment includes a rare earth garnet comprising A h B i C j O 12 , where h is 3±10%, i is 2±10%, and j is 3±10%. A includes a rare earth element or a mixture of rare earth elements, B includes at least one of aluminum, gallium and scandium, and C includes at least one of aluminum, gallium and scandium, where A is at a dodecahedral site of the garnet, B is at an octahedral site of the garnet, and C is at a tetrahedral site of the garnet. In one embodiment, the rare earth garment has scintillation properties. A radiation detector in one embodiment includes a transparent ceramic as described above and a photo detector optically coupled to the rare earth garnet.

What is claimed is: 
     
       1. A transparent ceramic, comprising:
 a rare earth garnet, 
 wherein the garnet comprises (Gd 1-a Y a ) x  (Ga 1a-b Al b ) y  O 12  RE z , where a is 0 to about 1; b is between about 0.44 and about 0.7; x is between about 2.8 and about 3.2; y is between about 4.8 and about 5.2; z is between about 0.002 and about 0.5; and RE is Ce and/or Pr; 
 wherein the transparent ceramic is characterized by a scatter coefficient less than about 0.1 cm −1 . 
 
     
     
       2. The transparent ceramic of  claim 1 , wherein the transparent ceramic is usable as a scintillating radiation detector. 
     
     
       3. The transparent ceramic of  claim 1 , wherein the rare earth garnet includes secondary phase inclusions in an amount less than about 0.2%. 
     
     
       4. The transparent ceramic of  claim 1 , wherein the ceramic is comprised of sintered particles. 
     
     
       5. The transparent ceramic of  claim 1 , wherein the ceramic is comprised of particles having interfaces therebetween characteristic of hot isostatic pressing. 
     
     
       6. The transparent ceramic of  claim 1 , further comprising a Sc in an amount of greater than 0 to about 16.67 atomic percent relative to a total amount of the Sc and the RE. 
     
     
       7. A radiation detector, comprising:
 the transparent ceramic of  claim 1 ; and 
 a photo detector optically coupled to the rare earth garnet. 
 
     
     
       8. The radiation detector of  claim 7 , wherein the radiation detector has an energy resolution at 662 keV of less than 5%. 
     
     
       9. The transparent ceramic of  claim 7 , wherein wherein the rare earth garnet includes secondary phase inclusions in an amount less than about 0.2%. 
     
     
       10. The transparent ceramic of  claim 1 , wherein the rare earth garnet includes secondary phase inclusions in an amount less than about 0.2%. 
     
     
       11. The transparent ceramic of  claim 1 , wherein b is between about 0.4 and about 0.6. 
     
     
       12. The transparent ceramic of  claim 1 , wherein b is between about 0.8 and about 0.99. 
     
     
       13. A transparent ceramic, comprising:
 a rare earth garnet comprising A h B i C j O 12 , the rare earth garnet having scintillation properties, 
 wherein h is 3±10%, 
 wherein i is 2±10%, 
 wherein j is 3±10%, 
 wherein A includes a rare earth element or a mixture of rare earth elements, B includes scandium and at least one of aluminum and gallium, and C includes at least one of aluminum and gallium , where A is at a dodecahedral site of the garnet, B is at an octahedral site of the garnet, and C is at a tetrahedral site of the garnet; 
 wherein the transparent ceramic is characterized by a scatter coefficient less than about 0.1 cm −1 . 
 
     
     
       14. The transparent ceramic of  claim 13 , wherein the garnet comprises (RE 3-u ,Sc u )(Al 2-x-v Ga x Sc v )(Al 3-y Ga y )O 12 , where x is 0 to about 2, y is 0 to about 3, u is 0 to about 0.5, and v is greater than 0 to about 2, wherein the rare earth garnet includes secondary phase inclusions in an amount less than about 0.2%. 
     
     
       15. The transparent ceramic of  claim 14 , wherein RE includes at least one of yttrium, gadolinium, lutetium, lanthanum, terbium, praseodymium, cerium samarium europium, dysprosium, holmium, erbium, ytterbium and/or mixtures thereof. 
     
     
       16. The transparent ceramic of  claim 14 , wherein x is 0 to about 1.5, y is 0 to about 2.5, u is 0 to about 0.25, and v is greater than 0 to about 1.5. 
     
     
       17. The transparent ceramic of  claim 14 , wherein x is 0, y is 0, u is 0 to about 0.5, and v is greater than 0 to about 2. 
     
     
       18. The transparent ceramic of  claim 14 , wherein x is 0 to about 2, y is 0 to about 3, u is 0. 
     
     
       19. The transparent ceramic of  claim 14 , wherein x is 0, y is 0, u is 0 to about 0.25, and v is greater than 0 to about 0.25. 
     
     
       20. The transparent ceramic of  claim 13 , wherein the garnet comprises (RE 3-u ,Sc u )(Ga 2-v ,Sc v )Ga 3 O 12 , where u is 0 to about 0.5, and v is 0 to about 0.5, wherein some Sc is present. 
     
     
       21. The transparent ceramic of  claim 13 , wherein the garnet comprises (Gd 1-a Y a ) x  (Sc 1-b Al b ) y  O 12  RE z , where a is between about 0.05 and about 1; b is between about 0.2 and about 0.99; x is between about 2.8 and about 3.2; y is between about 4.8 and about 5.2; z is between about 0.002 and about 0.5; and RE is Ce and/or Pr. 
     
     
       22. The transparent ceramic of  claim 13 , wherein the garnet comprises (Gd 1-a Y a ) x  (Ga 1-b Al b ) y  O 12  RE z , where a is between about 0.05 and about 1; b is between about 0.2 and about 0.99; x is between about 2.8 and about 3.2; y is between about 4.8 and about 5.2; z is between about 0.002 and about 0.5; and RE is Ce and/or Pr. 
     
     
       23. The transparent ceramic of  claim 13 , wherein the garnet comprises Gd x  (Ga 1-a Al a ) y  O 12  RE z , where a is between about 0.01 and about 0. 99; x is between about 2.8 and about 3.2; y is between about 4.8 and about 5.2; z is between about 0.002 and about 0.5; and RE is Ce and/or Pr. 
     
     
       24. A radiation detector, comprising:
 the transparent ceramic of  claim 13 ; and 
 a photo detector optically coupled to the rare earth garnet. 
 
     
     
       25. The radiation detector of  claim 24 , wherein the radiation detector has an energy resolution at 662 keV of less than 5%. 
     
     
       26. The transparent ceramic of  claim 13 , wherein the ceramic is comprised of sintered particles. 
     
     
       27. The transparent ceramic of  claim 13 , wherein the ceramic is comprised of particles having interfaces therebetween characteristic of hot isostatic pressing. 
     
     
       28. A system, comprising: the rare earth garnet as recited in  claim 13 ; and a photo detector optically coupled to the rare earth garnet, wherein the garnet comprises (Gd 1-a Y a ) x  (Ga 1-b Al b ) y  O 12  RE z , where a is between about 0.0 and about 0.7; b is between about 0.4 and about 0.7; x is between about 2.8 and about 3.2; y is between about 4.8 and about 5.2; z is between about 0.002 and about 0.05; and RE is Ce and/or Pr; wherein the transparent ceramic is characterized by a scatter coefficient less than about 0.1 cm −1 , wherein the radiation detector has an energy resolution at 662 keV of less than 5%. 
     
     
       29. A transparent ceramic, comprising:
 a rare earth garnet comprising (RE 1-a Sc a ) x (Al 1-b Ga b ) y O 12 , where a is about 0.05 to about 0.2, x is about 2.8 to about 3.2, b is 0 to about 1, and y is about 4.8 to about 5.2, wherein the rare earth garnet includes secondary phase inclusions in an amount less than about 0.2%. 
 
     
     
       30. The transparent ceramic of  claim 29 , wherein the transparent ceramic is characterized by a scatter coefficient less than about 0.1 cm 31 1 .